Now Americans go missing on Mars

Nasa scientists have lost contact with their Mars probe, it was announced last night.

The Spirit rover, a golf-cart-sized buggy designed to explore the surface of the red planet, has not responded for more than 24 hours.

Fears are growing that it has followed the fate of Britain's Beagle 2 lander. Nothing has been heard from that craft since it entered the Martian atmosphere on December 24.

US scientists were jubilant when their six-wheeled probe touched down safely on January 4 and then rolled on to the surface of the planet last week in preparation for three months of exploration.

Last night, they were desperately trying to re-establish contact with the £12 million buggy.

Pete Theisinger, the Spirit project manager, said the team was mystified by the loss of communication. "This is a serious problem," he added.

Nasa last heard from Spirit early on Wednesday as it prepared to continue examining its first rock, just a few yards from its lander. Since then it has sporadically returned random, meaningless radio noise.

Initially, the scientists believed weather problems on Earth were to blame, but they now think the rover is experiencing computer problems.

Nasa can fix software from Earth but if the problem lies with the hardware, the situation would be far graver, Theisinger said.

Spirit's identical sister craft, Opportunity, is scheduled to land on the opposite side of Mars on Saturday.

British scientists plan to resume trying to contact Beagle 2 on Monday, but hopes are fading for the £50 million mission.